Surface finishing



Dec. 26, 1939.

wf vH. FosTERg-r AL SURFACE FINISHING Filed Dec. 21, 1958 Nw `H; w

?atented Dec. 26, 1939 y UNITED .STATES PATENT OFFICE SURFACE FINISHING William H. Foster and Levi D. Tyson, Elkhart,`

Ind., assignors to Foster Machine Company, Elkhart, Ind., a corporation of `Indiana Application December 21, 1938, Serial No. 247,111

6 Claims. (Cl. 51-278) The present invention relates to improvements Referring to the drawing, certain sketches are in surface finishing. embodied therein illustrating the principles of According to certain modern methods which the present invention as applied to certain types are in use for finishing surfaces,`a finishing stone of surface which have been chosen by way of or the like is applied to the surface of the memexample. In said drawing- 5 ber to be finished, relative movement being pro- Figure 1 shows a cylindrical member having a vided between said members. By way of examfinishing stone in cooperative relationship with ple, if a rotary movement is communicated to the exterior surface thereof, together'l with means the member to be nished, a reciprocatory movefor driving said cylindrical member at a continment might be communicated tothe finishing uously varying speed; Y Y 10 stone, the direction of reciprocation of said stone Figure 2 is a plat illustrating the path of a being different from the direction of surface particle on the contacting surface of the finishmovement of the member tobe finished. Citing ing stone with respect to the surface of the cya simple example: If a cylindrical surface is to lindrical member at a certain speed of rotation be finished, the finishing stone might begiven of said cylindrical member; l5

a movement of reciprocation in a direction par- Figure 3 shows a corresponding plat for a. allel with the axis of said cylindrical surface. If l higher speed of rotation for said cylindrical memthe member to be finished is of a nature such that ber:

, it may not be conveniently moved, the movements Figure 4 shows a corresponding plat for a still of the finishing stone are controlled in such a higher speed of rotation of said cylindrical mem- 20 manner that they have components in a plurality ber; of directions out of parallelism with. each other. Figure 5 illustrates a member to be iinished In other words, the abrasive action of the stone having a fiat surface, and a stone for finishing should be such that the abrasions criss-cross each said fiat surface, said member and said stone other at a multiplicity of points, reducing the .having reciprocatory movements, together with 25 possibility of grooving. Itisl desirable in promeans for continuously varying the speed of reducing the finish above referred to, considering ciprocation of vthe member to be finished. any particular particle on the surface ofthe fin- Figures 6, 7'and 8 are plats in connection with ishing stone, that said particle shall'not retrace the structure of Figure 5, representing the path its path over the surface to be finished, or at taken by a particle on the surface of the iinish- 30 least that the number of such retracings shall be ing Stone With respect t0 the SllraCe t0 be fnminimized. ished at different ratios of relative speed between An object of the, present invention is to prosaid stone and said surface; vide improved means and an improved method Figure 9 iS a figure illustrating the aDDlCablfor finishing surfaces, whether they be ats or ity of the present invention to a stationary sur- 35 curved surfaces of constant radii or of variable face, the finishing stone being provided with comradii, which finishing will be accomplished withpound movements of reciprocation, the speed of out retracing the path of the finishing stone one of the components of said movement being with respect to the surface being finished. continuously varied relative to the speed of the A further object is to provide a means and a other of said components; 40 method for finishing surfaces which is simple and Figure 10 illustrates a member having a surexpeditious. face which may be the crowned face of a valve A further object is to provide a means and tappet, together with an annular stone for finmethod for finishing surfaces in which the ratio. ishing said Surface; and

of relative speeds of mo'sement between the iin- Figure 11 shows the surface of the valve tappet 45 ishing stone and the surface to be finished is conof Figure 10 with two curves traced thereon, one tinuously varied, to the end that the retracing in full lines and one in broken lines, illustrating of any portion of the path of the finishing memthe paths of a particular particle on the surface ber with respect to the surface to be finished-will of the finishing stone with respect to the correv be avoided. spending surface of the valve'tappet at two'dif- 50 A further object is to provide a means and a ferent ratios of rotative speeds of said stone and method for finishing surfaces -well adapted to said tappet. meet the needs of commercial service@V Referring rst to Figures 1 and 2 inclusive, the Further objects will appear as the description numeral 20 indicates a rotating cylindrical memproceeds. ber having the cylindrical surface 2l which is to 55 be finished. The numeral 22 indicates a finishing stone which in practice will be spring-pressed toward the cylindrical surface 2|, the face of the stone 22 being shaped to conform to said jcylindrical surface 2|. As indicated by the doublepointedarrow adjacent to the member 22, said member 22 is adapted to have a reciprocatory movement in a direction parallel'with the axis of the rotating cylinder member 20. The numeral 23 indicates a driving means for the cylindrical member 20, which driving means is adapted to drive said cylindrical member 20 at continuously progressively varying speeds. In other words, according to the present invention, the ratio between the surface speed of the reciprocating member 22 and the speed of the surface 2| is continually and progressively varied during the finishing operation. Assuming a constant speed of reciprocation of the stone 22 and a predetermined speed of the surface 2|, asparticular particle on the surface of the stone 22 will trace a path on the surface 2| approximating the plat appearing in Figure 2. Assuming that the speed of rotation of the cylindrical member 20 is continuously progressively varied, the path of travel of any particle on the contacting surface of the stone 22 will vary with respect to the surface 2|. Figures 3 and 4 show plats at different surface speed ratios between the stone 22 and the surface 2|. It will be clear that by reason of the continuous progressive variation in the ratio between the speeds of the stone 22 and the surface 2|, there will be no retracing of the path of contact therebetween while this variation in relative speeds is progressing in one direction. Accordingly, the finishing of the surface 2| -will be accomplished simply and expeditiously.

Referring now to Figures 5, 6, '7 and 8, the applicability of the present invention is illustrated in connection with a flat surface to be finished. A member having a flat surface is indicated by the numeral 25, and a stone for finishing said surface is indicated by the numeral 26. Said member 25 may be given a reciprocatory movement, sayin a horizontal direction as the parts are viewed in the drawing, whereas the stone 26 may be given a reciprocatory movement in a.

vertical direction. The numeral 21 indicates a driving means for the member 25, which operates at continuously progressively varying speeds. At a certain ratio of surface speeds the path of any particle on the stone 26 with respect to the surface of the member 25 may be represented by the plat appearing in Figure 6. According to the present invention this ratio of surface speeds is continuously and progressively changed. Figure 7 represents the path at a higher relative speed, and Figure 8 represents the path at a still higher relative speed.

In Figure 9 the member 25 to be finished may be held stationary, and the finishing stone 26 will be given a compound movement which has components of reciprocation both vertically and horizontally as the parts are viewed in the drawing. According to the present invention, the ratio of speeds between the vertical` component and the horizontal component will be continuously and progressively varied,'whereby the path of relative movement between the finishing stone 26 and the surface of the member', 25 will be continually varied and no portion of the path ofthe finishing stone relative to the member 25 will be retraced.

Referring to Figures 10 and 11, the numeral 28 indicates a rotating member having a surface generally normal to the axis of rotation. The member 28 may be a valve tappet such as used in motor cars, and may have a crowned surface.

The numeral 29 indicates an annular stone which overlies a portion of the surface of the tappet '28. As indicated by the arrows, the tappet 28 and the stone 29 may rotate in opposite directions. The shaft 30 of the rotating stone 29 will be provided with drivingf/ means, the speed of which may be continuously and progressively varied. Considering a particle on the finishing surface of the annular stone 29, the full line 3| may be said to approximate the path of such a particle at a certain ratio between the speed of rotation of the tappet 28 and the speed of rotation of the annular stone 29. The broken line 32 may be said to approximate the path of such a particle at a higher speed of rotation of the tappet with respect to the speed of rotation of the stone 29.

It will be understood, of course, that instead or progressively and continuously varying the speed of the surface to be finished, the speed of the finishing stone may bel continuously ,and progressively varied. A few examples of the applicability of the present invention have been chosen for illustration, and they will, it is thought, be sufficient to indicate to those skilled in the art the principles of the present invention'. There are, of course, many other applications, too numerous to recite. However, the examples chosen illustrate the advantages of continually and progressively varying the ratio between the surface speed of the member to be finished and the speed of the finishing stone during the finishing operation, to the end that criss-cross abrasive action is had between the finishing stone and the surface to be finished without the retracing of any portion of the path of contact. It is preferred, laccording to the present invention, to vary the relative speeds increasingly, so that the stone, While operating at the lower relative speeds, will remove a portion of the stock, and as the relative speed of the stone with respect to the surface to be nished is increased, the finish is improved and the stock removal becomes infinitesimal. It will be understood, of course, that if for anyspeclc purpose it is desired to modify the progression in the ratios of speed between the member to be finished and the finishing stone, it may be done Without departing from the present invention. For example, the variations in the speed ratlos may be uniformly continuous or non-uniformly continuous.

Though the present invention has been described in connection with the finishing of a plurality of types of surface, its applicability to other types of surface will be appreciated by those skilled in the art. It is intended to cover all modifications that fall within the scope of the appended claims.

What is claimed is- 1. The methd of finishing a surface of a member with a finishing utensil which consists in communicating positive movements to said member and to said utensil, the direction of contact surface movement of said utensil being continually different from the direction of contact surface movement of said member, the ratio between the speeds. of surface movements of said member and said utensil being continually and progressively varied.

2. The method of finishing a surface of a member which consists in applying a finishing utensil thereto, providing relative movement between said utensil and said member, which movement has reciprocatory components in at least two directions, and continuously progressively varying the ratio of speed between said components during the finishing operation,

3. The method of finishing a surface which consists in applying a finishing' utensil to said surface and providing'a continuously progresmember 'and said utensil being continually and progressively increased.

5. The method of finishing a surface of a.l

member which consists in applying a finishing utensil thereto, providing relative movement between said utensil and said member, which movement has reciprocatory components in at least two directions, and continuously yprogressively increasing the'ratio of speed between said components during the finishing operation.

6. Ihe method of finishing a surface which consists Vin applying a finishing utensil to said surface and providing a continuously progressively 'increasing ratio of relative speeds between said surface and said utensil in a criss-cross path. v

-WILLIAM H. FOS'I'ER.. D.MTYSON. 

